﻿#include "base64.h"  
//#include <iostream>  
  
static const std::string base64_chars =   
             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"  
             "abcdefghijklmnopqrstuvwxyz"  
             "0123456789+/";  
  
  
static inline bool is_base64(unsigned char c) {  
  return (isalnum(c) || (c == '+') || (c == '/'));  
}  
  
std::string base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len) {  
  std::string ret;  
  int i = 0;  
  int j = 0;  
  unsigned char char_array_3[3];  
  unsigned char char_array_4[4];  
  
  while (in_len--) {  
    char_array_3[i++] = *(bytes_to_encode++);  
    if (i == 3) {  
      char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;  
      char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);  
      char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);  
      char_array_4[3] = char_array_3[2] & 0x3f;  
  
      for(i = 0; (i <4) ; i++)  
        ret += base64_chars[char_array_4[i]];  
      i = 0;  
    }  
  }  
  
  if (i)  
  {  
    for(j = i; j < 3; j++)  
      char_array_3[j] = '\0';  
  
    char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;  
    char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);  
    char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);  
    char_array_4[3] = char_array_3[2] & 0x3f;  
  
    for (j = 0; (j < i + 1); j++)  
      ret += base64_chars[char_array_4[j]];  
  
    while((i++ < 3))  
      ret += '=';  
  
  }  
  
  return ret;  
  
}  
  
std::string base64_decode(std::string const& encoded_string) {  
  int in_len = encoded_string.size();  
  int i = 0;  
  int j = 0;  
  int in_ = 0;  
  unsigned char char_array_4[4], char_array_3[3];  
  std::string ret;  
  
  while (in_len-- && ( encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {  
    char_array_4[i++] = encoded_string[in_]; in_++;  
    if (i ==4) {  
      for (i = 0; i <4; i++)  
        char_array_4[i] = base64_chars.find(char_array_4[i]);  
  
      char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);  
      char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);  
      char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];  
  
      for (i = 0; (i < 3); i++)  
        ret += char_array_3[i];  
      i = 0;  
    }  
  }  
  
  if (i) {  
    for (j = i; j <4; j++)  
      char_array_4[j] = 0;  
  
    for (j = 0; j <4; j++)  
      char_array_4[j] = base64_chars.find(char_array_4[j]);  
  
    char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);  
    char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);  
    char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];  
  
    for (j = 0; (j < i - 1); j++) ret += char_array_3[j];  
  }  
  
  return ret;  
}
